1. Field of the Invention
This invention is related to hydroxyl-terminated poly(haloalkylene ethers). More particularly it is related to hydroxyl-terminated poly(haloalkylene ethers) wherein the halogen atoms are preferably bromine or chlorine, processes for their preparation and novel catalyst systems useful in said processes. In the case of hydroxyl terminated poly(chloroalkylene ethers) the products are substantially colorless.
For the purposes of convenience, the hydroxyl-terminated poly(haloalkylene ethers) are sometimes referred to hereinafter as polyols. For purposes of this disclosure, the term "polyols" includes materials which have at least one terminal hydroxyl group.
2. Description of the Prior Art
Hydroxyl-terminated poly(haloalkylene ethers) and processes for their preparation are known. Frequently the processes utilize cationic polymerization techniques wherein oxirane monomers (e.g., alkylene oxides), alcohols and acid catalysts are employed to synthesize hydroxyl-functional prepolymers. Thus, for example, see U.S. Pat. Nos. 3,850,856; 3,910,878; 3,910,879; and 3,980,579.
The products described in these patents have not proven entirely satisfactory. For example, it has been found very difficult to control the temperature of the polymerization during their preparation. Additionally the chloroalkylene products are dark in color and tend to be very slow to react with various materials such as isocyanates unless substantial quantities of catalysts are employed therewith. Furthermore these products have been found to be unstable upon exposure to light (e.g., sunlight) and heat (e.g., temperatures above 50.degree. C.). Thus they become even darker in color and increase in acidity and water content when exposed to such conditions. Still further the hydroxyl-terminated materials described in U.S. Pat. No. 3,980,579 adversely affect the catalytic activity of amine catalysts utilized in the preparation of polyurethane foam.
Other techniques for the preparation of hydroxyl-terminated poly(haloalkylene) ethers are also known. Thus U.S. Pat. No. 3,450,774 teaches the preparation of polymers having hydroxyl end groups by the cleavage of high molecular weight crystalline poly(epihalohydrin) in the presence of certain alkali compounds. The resulting polymers are crystalline and have low molecular weight. Moreover these polymers are only partially hydroxyl functional. Thus they may have carbonyl and ethynyl end groups in place of the hydroxyl end groups.
Other poly(haloalkylene ethers) are described in U.S. Pat. Nos. 3,636,163 and 3,850,857. The former patent describes the reaction of epibromohydrin and a phosphorous compound in the presence of a Friedel-Crafts catalyst. The latter patent describes the polymerization of epihalohydrin in the presence of a catalyst of a trialkyl onium salt of HMF.sub.6 wherein M is a Group V element.
The present invention provides novel hydroxyl-terminated poly(haloalkylene ethers), processes for the preparation of the polyols and catalyst systems useful therein. The chloroalkylene ethers of the present invention represent a preferred class of materials. They are optically clear and colorless (e.g., they appear to have the same optical clarity as distilled water). Thus they exhibit a color magnitude (described more fully hereinafter) of less than about 10. Moreover, they are stable to the affects of heat and light (i.e., they resist degradation due to such conditions). Moreover, they possess excellent chemical reactivity towards isocyanate materials.
The colorless hydroxyl-terminated poly(chloroalkylene ethers) of the present invention are particularly useful where the color of the finished product is important (e.g., where the true color of the product is critical). Thus, for example, these materials are particularly useful in the preparation of cast urethane systems which can be used for such things as flooring materials, coatings and adhesives. Moreover the urethanes produced with the materials of the invention have been found to exhibit improved properties over prior art urethanes. Thus, for example, such urethanes exhibit excellent resistance to grease and oil.